Crystal-rectifier.



P. C. RAWLS.

CRYSTAL RECTIFIER.

APPLICATION FILED DEc.3o, |914.

1,21 1,7 54. Patented Jan. 9,1917.

A PAUL C. RAWLS, 0F DES MOINES, IOWA.`

i cmrsTAL-ascrirmn.

Specication of Letters Patent.

Patented Jan. 9, 1917.

Originalapplication led July 6, 1914, Serial No. 849,298. Divided andthis application led December 30,

' 1914. Serial No. 879,801.

To all lwhom. it may concern:

Be it known that I, PAUL C. RAwLs, a

citizen of the United States, and resident o Des Moines, in the countyof Polk and State of Iowa, have invented a. certain new and usefulCrystal-Rectifier, of which the following` is a specification.

My invention relates to crystal rectifiers used in high frequencyoscillation detectors in wireless telegraphy or telephony.

The object of my invention is to provide an improved crystal rectifierof simple and inexpensive construction of increased efficiency andsensitiveness and of great durability or ruggedness, which is so mountedand arranged that it is not likely to get out of adjustment readily; andfurther in this connection to provide a crystal rectifier having a largenumber of points of maximum sensitiveness which may be easily found bythe operator and maintained in working position.

My invention consists in the construction, arrangement and combinationof the various parts of the device, whereby the objects contemplated areattained, as hereinafter more fully set forth, pointed out in my claimsand illustrated in the accompanying drawings,

Y )usted by means of a set screw 29. The

in which;

Figure 1 shows a side elevation of a crystal rectifier and means formounting the same, embodying my invention. Fig. 2

shows a vertical longitudinal sectional View,

of a portion of the mechanism. Fig. 3 shows an enlarged sectional viewof the contacting portions of my improved crystal faces of the crystalsof my improved crystal rectifier.

This application is a divisional of my copending application #7249,298,filed July 6, 1914.

It will, of course be understood that my improved crystal rectifier isemployed as ,a part of a mechanism. for detecting oscillations incarrying on the operations of wireless telegraphy and telephony.

In the exempliflcation of my invention illustrated in the accompanyingdrawings, I have used the reference numerals 10 and 11 to indicategenerally the binding posts of cup 15, which receives a zinkite crystal16,

and which is retained within the cup 15 by means of a quantity ofmercury amalgam 17 or the like. In the other binding post is a tube 18,having suitably mounted in it, a cylindrical body 19, which is providedwith a rod 20, extending through the tube 18, and having on its end anoperating head 21. An extensible coil spring 22 is received within thetube 18, and is adapted to yieldingly engage the body 19 and a stop 23for yieldingly pressing the body 19 longitudinally in a direction towardthe post 10.

0n the 'upper end of the body 19 is screwed a sleeve 24, on which is alaterally extending arm 25, which carries a chuck 26. The arm 25 extendsin the opposite direction from the sleeve 24. At one end, the armcarries the chuck 26, and to its other end is secured a contractiblecoil 27, which is operatively connected with an adjustable collar 28 onthe tube 18. The collar 28 may be adchuck 26 is designed to carryanother crystal, which is preferably a piece of copper pyrites 30, whichis mounted within a cup shaped container 32, and is held therein bymeans of a quantity of mercury amalgam 31. On the cup 32 is an arm 33adapted toV be held and gripped by the chuck 26. posts 10 and 11 areconnected by the wires 34 and 35 in a proper circuit.

Several improvements are accomplished by my improved crystal rectifier,one of them being the arrangement of the two counteracting springs 27and 22, so arranged that when the arm 25 is slightly rotated, the spring27 is stretched and after the copper pyrites crystal isin contact withthe zinkite crystal, as shown for instance in Figs. 3 and 5, there-willbe a'yielding pressure upon it,

'irstin a direction toward the zinkite crystal and second, in a rotarydirection relative to its contact point on the zinkite crystal, wherebyan improved contact point is made between the crystals. By rotating thehead 14, any part of the zinkite vcrystal may be brought into actualcontact with the copper pyrites crystal.

The

plished by my improved crystal rectifier, is

in the construction of the face, which is first attened and smoothed,and then it is cut or scored transversely in different directions, asillustrated for instance in Fig. 4, whereby the raised points are leftbetween the grooves, or cuts, or scores. These raised oints are shown inexaggerated form 'in' gig. 5, and are indicated by the referencecharacter 36. What I use is a zinkite crystal having an artificiallysmooth and polished surface, which is preferably artificial andregularly scarified or scored by means of draw filing or finesand-papering in two or more different directions, whereby a pluralityof very fine regular points are left on `.the polished surface. In thisconnection it may be mentioned that a number of smooth polished surfaceswill give the same or bet ter results, but necessitates the use of amuch reater ressure in holding the other memer of t e rectifier againstthe zinkite crystal, which will in many instances cause the othermember, which is frequently of softer material than the zinlritevcrystal to be crushed. The object in slightly scarifying the surfaces ofthe zinkite crystal is to obtain rectification with less pressureandwith the same or uniform result over the entire surface of thezinkite crystal.

I nd that improved results are obtainedV by using the copper pyritescrystal with a rounded point, as shown in Fig. 5, and the zinkitecrystal with the large number of points 36, as shown in said figure,insomuch as that when the crystals are in `the form shown, all of theraised points of the zinkite crystal are uniformly sensitive, and it istherefore easy for the operator, in adjusting these two crystalsrelative to each other, to

readily obtain an adjustment of maximum efficiency and rectification.

It willy be understood that some changes may be made in the constructionand the parts of my improved crystal rectieraparticularly in the methodof mounting the crystals, without departing from the essential featuresand purposes of my invention,

and it is my intent to cover by this appli- 50 cation any such changeswhich may be included within the scope of my claims.

I claim as my invention.

1. In a crystal rectifier, the combination of a sleeve, means forsupporting the sleeve, a body portion slidingly mounted in the sleeve, aspring for normally extending the body portion in one direction from thesleeve, a transverse arm on the outer end of" the body portion, acrystal holder at one end of the transyerse arm, and a spring connectedto the arm and adjustably mounted on the, sleeve, for the purposesstated.

2. In a crystal rectifier, the combination of a crystal holder,.a springfor normally projecting it toward the opppsite crystal, and a secondspring arranged 1n op osition to the rst an also capable of appying alateral tension to the crystal.

3. A crystal rectifier, comprising the combination-l of two adjacentcrystals, one having a relatively blunt point, andthe other having asmooth fiat polished surface provided with minute substantially regularand uniform projections, the blunt point being arranged to contact withsaid fiat surface.

p Des-Moines, Iowa, December 22, v1914.

PAUL o. RAwLs.

Witnesses J. MAHEB, A. SHERMAN.

